Bogdan Costisor 

Dear Bogdan, another mystery methinks. Good that you noticed that, as hope arises to have this corrected in the future.

If I place the bellow character in Office 365 Word, I can't navigate between the 2 symbols, because it's 1 glyph. Don't know what 2019 does, but latest Office does not allow you by default to navigate between them. It might be also a Windows specific thing, as fonts and rendering text can sometimes be related to some Windows specific functionalities.

fi

This symbol is a real ligature.

Later Edit: The above symbol is a standard ligature. Normally they can't be broken up, because they are meant to stay together (unless you intentionally disable ligature support). The ligatures that allow in between editing are not the standard ones. For example, the obligatory ligatures from Arabic where the symbols Lam and Alif are combined in an organic manner because that is how Arabic works, it's not just for better graphics, like in the case of standard ligatures.

I'm amazed of why the default behavior is to merge the 2 symbols. I think it's a font specific decision that the API respects. I do not control this, so the fix itself might be very tricky. I do not have full control not even over the actual font that is used. I do have a set of options I can enable/disable, but that will impact all fonts so I need to make sure I do not break ligatures for other languages. 

Bogdan Costisor said:

I'm amazed of why the default behavior is to merge the 2 symbols. I think it's a font specific decision that the API respects. I do not control this, so the fix itself might be very tricky. I do not have full control not even over the actual font that is used. I do have a set of options I can enable/disable, but that will impact all fonts so I need to make sure I do not break ligatures for other languages. 

Would using a default Windows font (currently Aptos or as previously Arial) for all languages using Latin or Latin like alphabet be an option? In my limited knowledge of the world maybe an option to give the user a choice of a serif and no-serif fonts at the Studio setup could be a valid way of working. Or maybe a choice from some few standard fonts for text display. This would apply then for all kind of views with or without visible formatting.

We use by default Segoe UI, as it's Windows' default font. However, when we get a font recommendation from the original file we try to use it. If the document uses Aptos, then Trados will try to use Aptos for the target file as well. With all this it's up to the API to decide what font to use. My setting is treated as a suggestion. The reason is a very compelling one. If you are translating from Latin to Chinese, your Latin font won't be good enough for Chinese, so the API adapts and changes your font to what you have available on you PC. This example is extreme, but I saw font changes even for Latin to Latin languages. I saw very often that even for German to Polish I get different font usages. 

Bogdan Costisor said:

I saw very often that even for German to Polish I get different font usages. 

I do work daily in that direction. Font changes result here usually, when the source font used does not support Polish diacritics. Last time I've seen that (it is already more than 4 years ago), was a PPTX file, where the PL diacritics got inserted in a different font. However, this does not happen when working without formatting shown. In such case my impression is, that Arial is used to show the text. But I have checked now and this was a wrong impression. It really looks Segoe is the font used when no formatting is shown. A good one, very nicely legible.

Thai ligatures work this way, so for some weird reason not only does the API automatically converts the 2 symbols into one, but also sends back that it's a combined ligature. Combined ligatures can be completely deleted with DELETE key, or remove ligature by ligature with the BACKSPACE key. The obligatory ligatures, from Arabic for example, work with both keys similarly. 

Yeah, one truth is that MS Office Word and by extension the DirectWrite API (the API I've been mentioning the whole time) will always try to draw your text as beautifully and readable as possible. So if a font would work better than your decision it will override it. Office might tell you that you are using Arial, but in reality it might use Arial Narrow or even completely other font family and you won't even have a clue it got swapped. They do this because having readable text is more important than using a specific font.

Bogdan Costisor said:

Yeah, one truth is that MS Office Word and by extension the DirectWrite API (the API I've been mentioning the whole time) will always try to draw your text as beautifully and readable as possible. So if a font would work better than your decision it will override it. Office might tell you that you are using Arial, but in reality it might use Arial Narrow or even completely other font family and you won't even have a clue it got swapped. They do this because having readable text is more important than using a specific font.

Horrible. It is me who wants to chose a font. Especially if I create my own documents, I will not use any of MS fonts. My font of choice is Myriad from Adobe. And Adobe products will hopefully keen what I want.

Thy will not use a font that is vastly different than what you suggested. But many fonts are similar so the API uses what it considers best. In the case of Myriad, it might decide to use other San Serif fonts. The swap is done due to some glyphs not being ideal for your rendering, so it's not a decision based on a whim, but actual necessity.  Again, you will see Myriad font, everything will tell you it's Myriad font, but when rendering it might change due to various issues. It won't impact visuals or how things works, it just doesn't tell you upfront: "Hey so for these 2 words I had to swap the font with another one because your glyph is not available in Myriad"